heinzboehmer's 2002 Topaz 6MT Coupe

[maupineda]

Coming back to this.

Have been driving the car around and keeping an eye on this leak. I've yet to see it leak any more and have not smelled any oil since I first noticed it.

I only noticed the smell after a track day, so I'm starting to suspect that the second half of the last sentence in the quote above is incorrect.

I'm guessing that what actually happened was that the tensioner had a small leak and the oil got flung around due to the g forces on track. Some made it onto (or close) to the exhaust manifolds (hence smell), some made it onto the tensioner boss on the head and some made it all the way to the water pump pulley (hence the oil trail near the belts).

So, plan is to replace the tensioner crush washer with an annealed one (thanks maupineda for the suggestion!) and go from there. Maybe this will end up being an easy fix?

This does really work, I was having a persistent leak when I replace the rack and annealed the washer and now is bone dry. I for sake of it, test it and you can bend them with the fingers after annealing so it does make the metal soft for a nice and easy ‘crush’

p.S. thanks for putting data to this! Spot on! The annealing also relieves stresses and at a much higher temp they will see in operation, so they won’t ‘anneal’ further which will prevent leaks overtime. My tensioner has been dry for the past two years.

you can also run a candle flame and the carbon residue goes off as you anneasl so you can use that as a gage, but seems the sharpie method is best. They will turn a bit orange and melt quickly after certain melt point is reached. I will be doing this with all my washers from now on.

[heinzboehmer]

I will be doing this with all my washers from now on.

Yep! I think I will too.

[heinzboehmer]

Got an unexpected EML light and limp mode yesterday. Here's a parsed down version of the DTCs I pulled with karter16's excellent tool:

• Active Codes
  • Error 0x88 - Idle-speed controller
    • Frequency: 1
    • Description: The DME was unable to regulate the engine to the specified idle-speed target. If no electrical fault for the idle actuator/ZWD is present, possible causes include contamination of the ZWD, blocked or disconnected hoses around the ZWD/idle-air distributor, or a throttle valve stuck open.
    • First Occurrence
      • Engine Speed: 1920 1/min
      • Relative Filling: 9.6 %
      • Idle Speed Controller Target Speed: 832 1/min
      • Adaptation Value For Loss Torque: 35.6 Nm
  • Error 0x90 - Lambda controller, bank 1
    • Frequency: 2
    • Description: The lambda control has exceeded its plausibility limits. If no electrical faults are stored, possible causes include throttle valves not closing correctly, unmetered air, intake leaks, idle-control actuator mechanical faults, or leaking/sticking fuel injectors.
    • First Occurrence
      • Engine Speed: 3040 1/min
      • Relative Filling: 25.6 %
      • Lambda Control Factor Bank 1: 0.695
      • Adaptation Factor (Multiplicative) Bank 1: 1
    • Second Occurrence
      • Engine Speed: 2320 1/min
      • Relative Filling: 23.2 %
      • Lambda Control Factor Bank 1: 0.695
      • Adaptation Factor (Multiplicative) Bank 1: 0.992
  • Error 0x91 - Lambda controller, bank 2
    • Frequency: 2
    • Description: The lambda control has exceeded its plausibility limits. If no electrical faults are stored, possible causes include throttle valves not closing correctly, unmetered air, intake leaks, idle-control actuator mechanical faults, or leaking/sticking fuel injectors.
    • First Occurrence
      • Engine Speed: 2360 1/min
      • Relative Filling: 36 %
      • Lambda Control Factor Bank 2: 0.695
      • Adaptation Factor (Multiplicative) Bank 2: 0.969
    • Second Occurrence
      • Engine Speed: 2880 1/min
      • Relative Filling: 27.2 %
      • Lambda Control Factor Bank 2: 0.695
      • Adaptation Factor (Multiplicative) Bank 2: 0.969
• Shadow Codes
  • Error 0x78 - Throttle valve potentiometer comparison
    • Frequency: 0
    • Description: Electrical fault present. Electronic throttle limp-home mode is active.
    • (No occurrences)
  • Error 0xDF - Intake manifold pressure
    • Frequency: 0
    • (No occurrences)

Active codes make me think something is up with the ICV. The rubber hoses in the idle path are all brand new and the valve itself is clean, but it could be failing electrically. The shadow codes are tripping me out though. Frequencies are 0, yet they're still reported and triggered limp mode? TPSs are also all pretty new (maybe 10k mi old?).

Cleared codes, drove the car around and only saw 0x88 come back (no limp mode). For now, gonna treat the shadow codes as red herrings and focus on the ICV.

On a related note, I've noticed that I've been much more clunky when pulling away from a stop lately. I thought I was just getting dumber and forgetting how to drive stick, but now I'm starting to think this is a symptom of a failing ICV. I do realize there is heavy confirmation bias involved in that last bit, but fortunately there's an easy way to prove out the theory.

Genuine part is on its way and will get swapped in soon. Price on it wasn't too crazy, so decided to just throw parts at the problem instead of spending a bunch of time diagnosing further. ICV lives right in one of the hottest parts of the engine bay and has been there for 24 years/150k mi at this point. Don't think it hurts to refresh it.

Once the new part is validated to work correctly, I'll take the old one apart to see what I find inside.

[Obioban]

The valve part of my ICV gets a soak in carb cleaner any time I have the intake manifold off.

[George Hill]

Never seen a bad ICV myself, I have seen a bad aftermarket one though, fixed with a used genuine one.

Keep us posted if it was the ICV.

[karter16]

The shadow codes are tripping me out though. Frequencies are 0, yet they're still reported and triggered limp mode? TPSs are also all pretty new (maybe 10k mi old?).

The shadow codes are probably there from when you replaced the TPS and connected the MAP sensor. Note that the "description" provided is a general one for the code in question, it's the other fields like "Error Type Interpretation" that give specifics of the error. If the frequency is zero and it hasn't emerged as an actual code you can ignore it :-)

[heinzboehmer]

Never seen a bad ICV myself, I have seen a bad aftermarket one though, fixed with a used genuine one.

Keep us posted if it was the ICV.

Will do! Agreed that it's a weird failure mode. Maybe it's a wiring or DME issue? Guess I'll find out soon.

The shadow codes are probably there from when you replaced the TPS and connected the MAP sensor. Note that the "description" provided is a general one for the code in question, it's the other fields like "Error Type Interpretation" that give specifics of the error.

Oh duh, I should have used the interpretation field instead. Good to know.

If the frequency is zero and it hasn't emerged as an actual code you can ignore it :-)

Hmm, but then why did the car go into limp mode? I don't think any of the active codes would have caused it...

Last time the TPSs or MAP were disconnected (on purpose) was before the last time I cleared error codes. I'm pretty sure of that since I was just recently messing with your SW tool

[karter16]

Hmm, but then why did the car go into limp mode? I don't think any of the active codes would have caused it...

Ummmm okay fair point. I'm going to do some digging.

[George Hill]

Maybe a question for karter16 I know there are faults that have to set twice before the CEL illuminates, are there situations were the DME needs a 2x occurrence before storing the fault? Could that be why the fault has a frequency of 0?

[karter16]

Maybe a question for karter16 I know there are faults that have to set twice before the CEL illuminates, are there situations were the DME needs a 2x occurrence before storing the fault? Could that be why the fault has a frequency of 0?

Yeah exactly that is why I said the shadow code isn't a problem, I thought that it had to trip the threshold before triggering the CEL and limp home mode, but possibly there are some failure modes that invoke limp home mode immediately?

[karter16]

It's going to take a while to go through cause its heckin complex but just had a look at the EGAS safety module stuff and the CSL version is different to standard M3 in that it takes (what I've named) rf_diag_st and rf_diag_sk_st as inputs. These are derived from a complicated lookup table against a bunch of error variables (including the idle speed controller ones) to work out what the failure mode is.

I'll trace it later when I have time, but my guess would be it's the ICV code that triggered limp home mode.

[karter16]

Maybe a question for karter16 I know there are faults that have to set twice before the CEL illuminates, are there situations were the DME needs a 2x occurrence before storing the fault? Could that be why the fault has a frequency of 0?

FWIW it's not always a 2x occurrence. The thresholds for triggering and aging out, as well as the increment values each time the error is reported is configured in the DTC table in the tune file:

e.g.



In this example (ICV code) fv_max is the count that has to be reached in order to be considered "present". In this case that is 0x14 (decimal 20). fv_inc defines the amount to increment the counter by each time the error is reported by the software. (in this case 5). So this error would have to be reported 4 times before triggering an actual code.

[heinzboehmer]

It's going to take a while to go through cause its heckin complex but just had a look at the EGAS safety module stuff and the CSL version is different to standard M3 in that it takes (what I've named) rf_diag_st and rf_diag_sk_st as inputs. These are derived from a complicated lookup table against a bunch of error variables (including the idle speed controller ones) to work out what the failure mode is.

I'll trace it later when I have time, but my guess would be it's the ICV code that triggered limp home mode.

To make this more confusing, I managed to trigger just the ICV code on the last test drive and got no limp mode

[karter16]

To make this more confusing, I managed to trigger just the ICV code on the last test drive and got no limp mode

Do you have the details of the code? I'm keen to see if there's any differences in the details of the code between the time it triggered limp mode and the time it didn't.

[heinzboehmer]

Do you have the details of the code? I'm keen to see if there's any differences in the details of the code between the time it triggered limp mode and the time it didn't.

Ah, good call. I didn't clear the latest code, so don't have it saved in your tool's history at the moment. I'll need to read it later since the car is taken apart and I don't want to trigger false codes just from having things unplugged.